I took carb off again and decided I'm going to do a 24 hour soak in solvent. Then blow it out. I was going to re-check my air-gap on the 'new' ignition modules while carb was off..But have decided I might as well take heads off and replace gaskets. If I can get muffler off I'll replace Head bolts with studs..But need muffler off to do that so as to have the room to 'slide' head over them. Muffler appears ok if I go with standard head bolts. I will also 'Lap' the valves while apart. Now my question: being it has hydrolic lifters..(A)should I replace them assuming I can get them out,to eliminate any possibility one is getting bad? (B) with hydrolic lifters there are no valve adjustment right? just rocker arm torque as well as Head torque? Does this sound like good plan? Previous post stated It was only running on loss of power (miss/black smoke/was running good first few minutes..worse now) Thanks- Gene P.S.- thought it might be SAM..but don't appear this motor has that-nothing under cover.